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针对飞机故障预测和健康管理系统中提出的损伤扩展预测与结构剩余寿命管理的要求,提出了一种粒子滤波与结构健康监测方法相结合的结构疲劳裂纹扩展预测方法。首先采用ABAQUS_Python二次开发软件,实现了对裂尖奇异单元网格的自动划分,进而得出不同裂纹长度、角度下裂纹尖端处的应力强度因子幅,提出采用二参数的Paris规则建立粒子滤波的状态方程,即损伤及寿命的扩展演化模型;采用基于压电元件和主动Lamb波的结构健康监测方法,实时观测更新裂纹信息并同粒子滤波算法相结合,建立了粒子滤波的观测方程。疲劳载荷作用下的裂纹扩展实验结果表明,20 000次循环载荷后预测裂纹扩展长度误差在2%以内。本文方法可以有效预测结构裂纹的扩展,消除Paris规则预测裂纹扩展的误差累积及工程应用中多种不确定性的影响。
Aiming at the requirements of aircraft damage prediction and health management system for damage extension prediction and structure residual life management, a structural fatigue crack growth prediction method based on particle filter and structural health monitoring is proposed. Firstly, the secondary development of ABAQUS_Python software was used to realize the automatic meshing of singular cell with crack tip, and then the stress intensity factor at crack tip under different crack length and angle was obtained. The Paris rule with two parameters was proposed to establish the particle filter State equation, which is the evolution model of damage and life span. The structural health monitoring method based on piezoelectric element and active Lamb wave is used to observe and update the crack information in real time and combine with the particle filter algorithm to establish the observation equation of particle filter. The experimental results of crack propagation under fatigue load show that the predicted error of crack propagation length after 20 000 cycles is within 2%. The proposed method can effectively predict the propagation of structural cracks and eliminate the effects of multiple irregularities in engineering application predicted by Paris rule.